State Preemption of Local Zoning in Connecticut

What Is State Preemption?

State preemption occurs when a state law overrides local government ordinances in a specific area. In land use, preemption means a city or county cannot adopt zoning rules that are more restrictive than the state standard. If a city tries to prohibit something the state law permits, the state law wins.

Connecticut actively uses preemption in housing law. The state has enacted legislation that prohibits local governments from blocking certain types of housing development — most notably accessory dwelling units (ADUs) and lot splits.

ADU Preemption

What local governments cannot restrict:

• ✓ADUs must be permitted ministerially — no discretionary review or public hearing required
• ✓Local regulations may set reasonable development standards (setbacks, size limits, design) but may not effectively prohibit ADUs
• ✓Owner-occupancy of either the primary or accessory unit may be required by local ordinance
• ✓Municipalities that did not adopt compliant ADU ordinances by a certain deadline are subject to state override

How Preemption Affects Connecticut Cities

State preemption applies to every incorporated city and unincorporated area in Connecticut. Select a city below to see how state preemption interacts with local zoning rules.